1. Field of the Invention
The present invention relates to a touch control system and related touch control method and computer system, and more particularly, to a touch control system and related touch control method and computer system with high compatibility.
2. Description of the Prior Art
Graphical user interface is an easy-to-use computer interface, which displays graphics such as windows, icons, buttons, on a screen, such that a user can select graphics via a pointing device to execute different operations. In the prior art, except for mice, touch pads are most widely used pointing devices in computer systems. The touch pads are widely used in laptops, because the touch pads can be installed in the laptops with the benefit of portability. Among all touch control methods for the touch pads, a capacitive touch technique is the most popular touch technique due to stable performance, excellent sensitivity and durability.
In general, the capacitive touch technique detects capacitive variations generated by static electricity combinations to determine a touch event when a human body touches a point on the touch panel. In other words, the capacitive touch technique realizes touch control operations by measuring the difference of capacitance after a point on the touch panel is touched. Please refer to FIG. 1, which is a schematic diagram of a conventional capacitive touch sensing device 10. The capacitive touch sensing device 10 includes sensing capacitor chains X1˜Xm and Y1˜Yn. Each sensing capacitor chain includes a plurality of sensing capacitors connected in series. The conventional touch detection method detects the capacitance of each sensing capacitor chain to determine whether a touch event occurs. If the sensing capacitor chain X1 includes Q sensing capacitors, and the capacitance of each sensing capacitor is C, the capacitance of each sensing capacitor chain is QC. When the human body (e.g. a finger) touches one sensing capacitor of the sensing capacitor chain X1, the capacitance variation of the sensing capacitor chain X1 is ΔC. If the capacitance of the sensing capacitor chain X1 is (QC+ΔC), the finger is touching the sensing capacitor chains X1. As shown in FIG. 1, when the finger touches the touch point A (X3, Y3), both sensing capacitor chains X3 and Y3 sense the capacitance variation, such that the capacitive touch sensing device 10 can determine that the touch sensing point is (X3, Y3).
However, a false determination may occur in a multi-touch operation. For example, please refer to FIG. 2, which is a schematic diagram of a multi-touch operation of the capacitive touch sensing device 10. As shown in FIG. 2, since two fingers touch the capacitive touch sensing device 10 at the same time, the sensing capacitor chains X3, Xm−1, Y3, and Yn−1 sense a capacitance variation at the same time as well, such that the capacitive touch sensing device 10 would determine that the touch events are occurring at (X3, Y3), (X3, Yn−1), (Xm−1, Y3), and (Xm−1, Yn−1). However, only the points (X3, Y3) and (Xm−1, Yn−1) are touched, while the points (X3, Yn−1) and (Xn−1, Y3) are not actually touched. In such a situation, the capacitive touch sensing device 10 falsely determines that the points (X3, Yn−1) and (Xn−1, Y3) are touched, causing “ghost keys”. Therefore, the capacitive touch sensing device 10 can only determine at which crossing sections of the sensing capacitor chains a touch event may occur in the multi-touch operation, but can not accurately determine which points are actually touched. For the multi-touch operation, conventional touch pads operate in an absolute mode via a corresponding driving program to determine and complete user instructions. Detailed descriptions are as follows.
Please refer to FIG. 3, which are schematic diagrams of a touch pad of a computer system operating in a relative mode and an absolute mode, respectively. A left side of FIG. 3 indicates the relative mode, while a right side of FIG. 3 indicates the absolute mode. In short, in the relative mode, the touch pads simply reports a variation of touched points to an internal driving program, in order to complete the user instruction. In the absolute mode, the touch pad reports all sensed touch information to the corresponding driving program, which determines and executes the corresponding user instruction. In detail, in the relative mode, the touch pad generates sensed signals in 4-byte packets after calculating a variation of touched points. The sensed signals are transferred via an embedded controller, for reporting touch information such as a variation of touched points and whether a button is enabled (ΔX, ΔY, ΔZ, B) to an internal driving program, such that the system can execute the user instruction accordingly. Therefore, for the multi-touch operation, since the touch pad can not determine which point are actually touched, the touch pad can not report a variation of touched points to the internal driving program, such that the system can not executes the user instruction. In the absolute mode, the touch pad generates sensed signals in 6-byte packets according to touch information such as touched points, button status, whether the touch pad is in a multi-touch operation, pressure (X, Y, B, M, W), etc. Then, the sensed signals are reported to the corresponding driving program via the embedded controller, such that the system and the corresponding driving program can accordingly calculate a variation of touched points (such as a distance, a scroll operation), and execute the user instruction. Therefore, for the multi-touch operation, the touch pad reports the sensed signal of each touched point to the corresponding driving program via the embedded controller, and the corresponding driving program determines the corresponding user instruction, such that the system can execute the user instruction. Therefore, in the absolute mode, the touch pad can utilize the corresponding driving program to determine the user instruction in the multi-touch operation.
However, some touch pads or touch sensing devices need to operate with the corresponding driving program, or some basic or specific user instructions can not be executed, limiting application scope. In other words, when the system is not installed with the corresponding driving program, the touch pads or the touch sensing devices can not be fully utilized. For example, please refer to FIG. 4, which is a schematic diagram of an operation of a conventional touch pad 40. Under the lower left and right side dotted line areas Area_L and Area_R are a left button Pad_L and a right button Pad_R of a ordinary touch pad, respectively, and the left button Pad_L and the right button Pad_R are enabled after an external force greater than a predefined magnitude is received, such that a size of the touch pad 40 can be minimized. Under such a situation, assume that a user uses one finger to press a point A to enable the left button Pad_L, and another finger to move from a point B to a point C (i.e. a dragging operation). In the relative mode, since the touch pad senses two-point touch operation of the point A and a movement from the point B to the point C, the touch pad can not determine which points are actually touched, so as not to reported a variation of touched points to the internal driving program, such that the user instruction can not be executed; in the absolute mode, the touch pad reports all sensed information of the point A and a movement from the point B to the point C to the corresponding driving program, which determines the corresponding user instruction, such that the system can operate according to the user instruction. As can be seen from the above, the touch pads 40 needs to operate with the corresponding driving program in the absolute mode, or some basic operations inputted by the buttons can not be executed. In other words, the touch pads 40 can not operate with the internal driving program in the relative mode.
Therefore, for this type of touch pad, if an operating system of the computer is not installed with a corresponding driving program, even some basic operations inputted by the buttons can not be executed. Thus, there is a need for improvement.